With more than 200 towers of heights 20 stories or greater planned to be built in London over the next 20 years, the UK's capital city is in for some big visual changes. Architectural visualization firm Hayes Davidson places those planned towers over a current image of London to imagine the future shape of London's skyline.

This particular visualization adds 13 completed large buildings to London—including the Pinnacle by Kohn Pedersen Fox and Foggo Associates' 60-70 St. Mary's Axe (known as the "Can of Ham")—and is one of the images that will be featured in the upcoming exhibition London's Growing... Up!, which opens at New London Architecture on April 3rd, 2014. The exhibition explores the past, present, and future of London architecture and will let visitors design their own London skyline. If you can't make it to the NLA, however, you can play with Hayes Davidson's interactive London skyline tool from home, adding and placing all sorts of buildings (even those from other cities) in London. The firm also has a number of other visualizations on its site, picturing the possible architectural future of New York and London: